Description

Simple

A medication used to treat serious cases of low blood pressure, often during surgery when anesthesia is used and leads to low blood pressure.

Clinical

An alpha-1 adrenergic agonist used in the management of hypotension, generally in the surgical setting associated with the use of anesthetics.

Overview

Phenylephrine is an alpha-1 adrenergic receptor agonist used to treat hypotension,[6,8] dilate the pupil,[7] and induce local vasoconstriction.[1] The action of phenylephrine, or neo-synephrine, was first described in literature in the 1930s.[2]

Phenylephrine was granted FDA approval in 1939.[7]

Pharmacology

Indication

Phenylephrine injections are indicated to treat hypotension caused by shock or anesthesia,[6, Read more

Pharmacodynamic

Phenylephrine is an alpha-1 adrenergic agonist that raises blood pressure,[6, Read more

Mechanism of action

Phenylephrine is an alpha-1 adrenergic agonist that mediates vasoconstriction[1] and mydriasis[ Read more

Absorption

Phenylephrine is 38% orally bioavailable.[3] Clinically significant systemic absorption of ophth... Read more

Protein binding

Data regarding the protein binding of phenylephrine in serum is not readily available.[6, Read more

Volume of distribution

The volume of distribution of phenylephrine is 340L.[6, Read more

Clearance

Phenylephrine has an average clearance of 2100mL/min.[6, Read more

Half life

Intravenous phenylephrine has an effective half life of 5 minutes and an elimination half life of 2.5 hours.[ Read more

Route of elimination

86% of a dose of phenylephrine is recovered in the urine[3] with 16% as the unmetabolized drug,... Read more

Toxicity

Patients experiencing and overdose may present with headache, hypertension, reflex bradycardia, tingling limbs, cardiac arrhythmias, and a feeling of fullness in the head.[ Read more

Adverse Effects

Contraindications

  • Route:
    • Intramuscular
    • Subcutaneous
  • Dose Form:
    • Injection
  • Regions: US
  • Patient Conditions:
      • Name: Severe Hypertension
      • Drugbank Id: DBCOND0058109
      • Modification Of:
        • Base:
          • Name: Hypertension
          • Drugbank Id: DBCOND0020037
        • Severity:
          • Includes:
            • severe
  • Route:
    • Intramuscular
    • Subcutaneous
  • Dose Form:
    • Injection
  • Regions: US
  • Patient Conditions:
      • Name: Ventricular Tachycardia
      • Drugbank Id: DBCOND0031960
  • Route:
    • Ophthalmic
  • Regions: US
  • Patient Conditions:
      • Name: Thyrotoxicosis
      • Drugbank Id: DBCOND0021770
  • Route:
    • Ophthalmic
  • Regions: US
  • Patient Conditions:
      • Name: Hypertension
      • Drugbank Id: DBCOND0020037
  • Route:
    • Ophthalmic
  • Hypersensitivity:
    • false
  • Regions: US
  • Route:
    • Ophthalmic
  • Regions: US
  • Age Groups:
    • pediatric
  • Below Age:
    • Amount: 1
    • Unit: year

Food Interactions

    Information currently not available.

Interactions

Type in a drug name to check for interaction with Phenylephrine
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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The metabolism of (R)-warfarin can be increased when combined with Phenylephrine.
1-benzylimidazole
The risk or severity of hypertension can be increased when Phenylephrine is combined with 1-benzylimidazole.
2,5-Dimethoxy-4-ethylamphetamine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 2,5-Dimethoxy-4-ethylamphetamine.
2,5-Dimethoxy-4-ethylthioamphetamine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 2,5-Dimethoxy-4-ethylthioamphetamine.
3-isobutyl-1-methyl-7H-xanthine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 3-isobutyl-1-methyl-7H-xanthine.
3,5-diiodothyropropionic acid
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 3,5-diiodothyropropionic acid.
3,5-Diiodotyrosine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 3,5-Diiodotyrosine.
4-Bromo-2,5-dimethoxyamphetamine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 4-Bromo-2,5-dimethoxyamphetamine.
4-Methoxyamphetamine
The metabolism of Phenylephrine can be decreased when combined with 4-Methoxyamphetamine.
5-methoxy-N,N-dimethyltryptamine
The risk or severity of hypertension can be increased when Phenylephrine is combined with 5-methoxy-N,N-dimethyltryptamine.
6-O-benzylguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 6-O-benzylguanine.
7-Deazaguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 7-Deazaguanine.
7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline
7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline may increase the hypertensive activities of Phenylephrine.
7,9-Dimethylguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 7,9-Dimethylguanine.
8-azaguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 8-azaguanine.
8-chlorotheophylline
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 8-chlorotheophylline.
9-Deazaguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 9-Deazaguanine.
9-Methylguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 9-Methylguanine.
Abaloparatide
The risk or severity of adverse effects can be increased when Phenylephrine is combined with Abaloparatide.
Abediterol
The risk or severity of hypertension can be increased when Phenylephrine is combined with Abediterol.
8 References
  1. 1 . Richards E, Maani CV: Phenylephrine .PubMed: 30521222
  2. 2 . Prescott F: CLINICAL EVALUATION OF THE PRESSOR ACTIVITY OF METHEDRINE, NEO-SYNEPHRINE, PAREDRINE, AND PHOLEDRINE. Br Heart J. 1944 Oct;6(4):214-20. doi: 10.1136/hrt.6.4.214.PubMed: 18609981
  3. 3 . Kanfer I, Dowse R, Vuma V: Pharmacokinetics of oral decongestants. Pharmacotherapy. 1993 Nov-Dec;13(6 Pt 2):116S-128S; discussion 143S-146S.PubMed: 7507589
  4. 4 . Bairam AF, Rasool MI, Alherz FA, Abunnaja MS, El Daibani AA, Gohal SA, Alatwi ES, Kurogi K, Liu MC: Impact of SULT1A3/SULT1A4 genetic polymorphisms on the sulfation of phenylephrine and salbutamol by human SULT1A3 allozymes. Pharmacogenet Genomics. 2019 Jul;29(5):99-105. doi: 10.1097/FPC.0000000000000371.PubMed: 31145702
  5. 5 . Gelotte CK, Zimmerman BA: Pharmacokinetics, safety, and cardiovascular tolerability of phenylephrine HCl 10, 20, and 30 mg after a single oral administration in healthy volunteers. Clin Drug Investig. 2015 Sep;35(9):547-58. doi: 10.1007/s40261-015-0311-9.PubMed: 26267590
  6. 6 . FDA Approved Drug Products: Phenylephrine Solution for Intravenous Injection Link
  7. 7 . FDA Approved Drug Products: Phenylephrine Ophthalmic Solution Link
  8. 8 . FDA Approved Drug Products: Phenylephrine Intravenous Injection (Ready to Use) Link